SD Cards (Part 1)
Other posts on same subject Part 1, 2, 3, 4, 5, 6
SD card are really convenient electronic devices for storing huge amounts of data. Their are used in so many appliances (e.g. Digital Cameras, MP3) that their price is ridiculously low compared to IC’s.
Interfacing the SD to Arduino is as simple as soldering 6 resistors together in order to make voltages compatible. The 3.3 V is taken from the power supply header, which is fed by the FTDI interface chip.
Note: The use of higher resistor values may lead to unstable operation. A nicer and more reliable solution consists in using a transreceiver.
You can also use Adafruit shield for music and sound which includes a SD socket.
Pinout
pin 1: CS, SS
pin 2: DATAIN, MOSI
pin 3: VSS1, GND
pin 4: VDD, 3.3v VCC
pin 5: CLK, SCK
pin 6: VSS2, not connected
pin 7: DATAOUT, MISO
pin 8: DAT1, not connected
pin 9: DAT2, not connected